What Causes Headache And Loss Of Appetite?

my son has had a headache on the right side of his head for the last 2 weeks, he is sleeping 16 to 18 hours out of every 24. the doctor has ruled out migraine. He is not eating well and just wants to sit around a watch tv when he is awake. He says that it doesn't make any difference taking pain killers, watching tv or reading doesn't make it worse, but nothing makes it better.